Method and device for producing a container filled with a liquid filling material

ABSTRACT

A method and a device for producing a container filled with a liquid filling material from preforms made of a thermoplastic material, wherein each preform is thermally conditioned and subsequently, during a molding and filling phase, remolded into the container in a mold having at least one liquid filling material as a pressure medium. The filling material or parts of the filling material are supplied at at least two points in time and/or in at least two process phases with different contents of carbon dioxide and/or at different temperatures. In the second process phase, dry ice, particularly in form of pellets, is supplied.

The present application is a 371 of international applicationPCT/EP2013/002268, filed Jul. 31, 2013, which claims priority of DE 102012 015 087.3, filed Aug. 1, 2012, the priority of these applicationsis hereby claimed and these applications are incorporated herein byreference.

BACKGROUND OF THE INVENTION

The invention concerns a method for producing containers filled with aliquid filling material from thermoplastic preforms as well as a devicefor producing the containers filled with the liquid.

The production of containers by blow molding from preforms made of athermoplastic material is well-known, for instance from preforms made ofPET (polyethylene terephthalate), whereas the preforms are conveyed tovarious machining stations inside a blow molding machine (DE-OS 43 40291). Typically, a blow molding machine includes a heating device fortempering or preheating (thermal conditioning) of the preforms as wellas a blow molding device with at least a blow molding station, in whicharea the preform previously tempered is expanded biaxially ormultiaxially to become a container. The expansion takes place with theaid of a compressed gas (compressed air) as a pressure medium, which isintroduced into the preform to be expanded with a forming pressure. Theprocess-related sequence of such an expansion of the preform isexplained in document DE-OS 43 40 291.

The basic construction of a blow molding station is described in DE-OS42 12 583. The possible tempering methods of the preforms are explainedin DE-OS 23 52 926.

According to a typical further processing treatment, the containersproduced by blow molding are conveyed to a subsequent filling device andthen filled with the product or filling material provided. A separateblow molding machine and a separate filling machine are thus used. It isalso known to regroup the separate blow molding machine and the separatefilling machine to obtain a machine block, i.e. to obtain a blocked blowmolding and filling device, whereas the blow molding and the fillingcontinue to be performed at distinct machine components andchronologically one after the other.

It has been moreover already suggested, to produce containers, inparticular in the form of bottles, from thermally conditioned orpreheated preforms and thereby to fill them simultaneously with a liquidfilling material, which is conveyed as a hydraulic pressure medium forexpanding the preform or for shaping the container with a forming andfilling pressure so that the respective preform is transformed into thecontainer at the same time as the filling process. Such methods, atwhich simultaneous forming and filling of the respective container takesplace, can be designated as a hydraulic transformation method orhydraulic formation of containers.

During the formation of the containers from the preforms by the fillingmaterial, i.e. by using the filling material as a hydraulic pressuremedium, only one machine is necessary to form and fill the containers,which in turn exhibits an increased complexity. The first experimentalresults with such devices indeed show that the quality of the producedcontainers is still significantly lower than the quality ofconventionally produced blow formed containers. The cause is among otherthings that a multiplicity of process parameters which are availablewhen performing the usual blow molding process, parameters which areeither absent during the hydraulic formation of containers or cannot beexploited as yet.

There is a particular problematic with the hydraulic formation ofcontainers inasmuch as any contamination should be avoided for therespective forming and filling station or of the mould constituting saidstation, which mould is similar to a blow mould of a blow moldingmachine for the production of containers from thermally conditionedpreforms by blowing with a compressed gas. Especially in the case of afull or partial carbonation of the filling material, there is in aparticular extent the danger of a contamination of the respectiveforming and filling station through losses of filling material, inparticular when lowering the inside pressure of the container, i.e. whenrelieving the container from the quite high forming and filling pressuredown to the ambient pressure. Such losses of filling material areconditioned in particular by a massive foaming during the relievingprocess so that the simultaneous forming and filling of containers byusing preforms and by using the filling material as a pressure medium(hydraulic transformation technique), in particular for CCV-containingproducts could not be contemplated so far.

SUMMARY OF THE INVENTION

The object of the invention is to provide a method which avoids thedanger of any contamination of the respective forming and fillingstation even with a CCV-containing filling material, during thehydraulic transformation method or during the hydraulic forming ofcontainers, especially with high throughputs (number of the formed andfilled containers per time unit) and/or with a high CO₂ content of thefiling material introduced into the respective container.

In the method according to the invention, preforms made of athermoplastic material are thermally conditioned and subsequentlytransformed into the container during a forming and filling phase insideof a mould with at least one liquid filling material as a pressuremedium.

In this process, the filling material or portions of the fillingmaterial are supplied at least at two points in time and/or in at leasttwo process phases with different carbon dioxide contents and/or withdifferent temperatures, The method according to the invention ischaracterized in particular in that in the second process phase dry iceis conveyed in particular in the form of pellets.

Preferably, degassed filling material is conveyed in one process phase.The CO₂ content is then equal to zero or close to zero according to thedegree of degassing.

The filling material can then be carbonized in the second process phasewhen the filling material with higher carbon dioxide content isconveyed. The carbonization can take place completely or partially byadding carbon dioxide in the form of dry ice. Dry ice can be conveyed inthe form of pellets, for instance at the filling material surface or inthe region of the container bottom. The dry ice can be inserted into thefilling material or shot into the filling material.

In complement thereto, the carbonization can also partially take placeat at least 1 bar, preferably between 1 and 2 bars above the respectivesaturation pressure, which depends on the temperature of the filingmaterial.

To guarantee the best possible product quality, the respective preformis preferably guided, during its transformation into a container bubblein formation and then into the container having the final contour orshaping, so that a centre is defined, typically in the region of apreform summit, and can be positioned reproducibly. Such a definedpositioning is important since during the transformation or expansion ofthe preform into the container, a biaxial orientation of the material ofthe preform is performed, and to do so, a targeted and predefinablematerial distribution inside the wall of the formed container isrequired. In contrast, if the formation of containers is not perfectlycontrolled, undesirable and particularly irregular materialdistributions can be expected.

Guiding during the forming and filling phase can be particularlyefficient by using a stretching bar or a stretching rod, whereas thefilling material is conveyed e.g. at least partially through thestretching rod. Alternatively or in complement thereto, the fillingmaterial can at least partially also be conveyed past the stretchingrod.

It is possible to achieve regular and hydraulic formation of containersby conveying the filling material at least temporarily with a constantvolume flow rate. Possibilities to influence the material distributioninside the wall of the container in formation or readily shaped is toconvey the filling material at least temporarily with a variable volumeflow rate.

A very compact construction is facilitated by forming, filling andclosing the containers on a rotating process wheel or rotor.

A further embodiment consists in measuring the generated stretchingforce. Only low stretching forces to be exerted by the stretching rodcan be achieved by controlling the volume flow rate of the fillingmaterial according to the stretching force measured.

Independent of the aforementioned features or in addition to thesefeatures, the method according to the invention is preferably furtherimproved in such a way

that degassed filling material is conveyed during the first processphase,

and/or that during the second process phase the filling material or theportion of filling material with the higher concentration of carbondioxide is conveyed,

and/or that the filling material or the portion or more precisely thecomponent of the filling material with the higher concentration of CO₂is cooled prior to the introduction and in the second process phase thefilling material or the portion of filling material with the higherconcentration of CO₂ has a lower temperature than the filling materialor the portion of filling material of the first process phase,and/or that the carbon dioxide content or CO₂ content in a secondprocess phase is 30% in weight, preferably 50 to 100% in weight greaterthan the CO₂ content of the first phase,and/or that the temperature of the filling material or of the portion offilling material of the second process phase is lower than 10° C., inparticular ranges between 4° C. and 8° C.,and/or that the pressure of the filling material or of the portion offilling material, which has the higher carbon dioxide concentrationand/or the lower temperature, is at least temporarily during the formingprocess higher than at least one other portion or the rest of thefilling material, and in particular is higher by at least 1 bar,and/or that the pressure on a partial conduit distance is higher thanthe pressure of the filling material or of the portion of fillingmaterial which has the higher carbon dioxide concentration and/or thelower temperature, preferably at least temporarily during the formingprocess or during the forming and filling phase is higher by 2 bars to 5bars than at least one other portion or the rest of the fillingmaterial,and/or that a throttle element or a narrowing cross-section is providedin the flow path of the filling material or of the portion of thefilling material flowing inside the stretching bar, whereas the throttleelement is arranged in particular close to at least one outlet formed atthe stretching rod,and/or that a portion of the filling material is guided past thestretching rod and a portion of the filling material is guided throughthe stretching rod,and/or that the portion of the filling material with the higher CO₂content is cooled,and/or that the portion of the filling material with the higher CO₂content is conveyed through the stretching rod,and/or that the stretching rod is thermally insulated at least incertain areas with respect to the filling material,whereas the aforementioned features can be provided respectivelyindividually or in any combination.

The device according to the invention is fitted with a heating line forpreheating the preforms and with at least one forming and fillingstation having a mould, as well as with at least one supply device toprovide the filling material, whereas preferably a carbonation unit isprovided for introducing or dissolving carbon dioxide at least into apartial flow of the filling material. The device according to theinvention is characterized in that said at least one forming and fillingstation is fitted with at least one device for supplying dry ice, inparticular in the form of pellets.

The device of the invention may as an enhancement of the inventionpreferably be designed in such a way

that a cooling unit is provided along a conduit or a conduit section forthe respective portion of the filling material in which (portion)downstream, i.e. after cooling and flowing through the conduit section,carbon dioxide is dissolved or which flows towards the conduit from thecarbonation unit,and/or that at least the conduit section in which the filling materialor the portion of the filling material with the high CO₂ content isguided is insulated, in particular with an insulation consisting ofTeflon or of a Teflon-containing material,and/or that at least the conduit section in which the filling materialor the portion of the filling material with the high CO₂-content isguided is cladded with an insulation, for instance with Teflon or aTeflon-containing material,whereas the aforementioned features can be provided respectivelyindividually or in any combination.

Further developments, advantages and application possibilities of theinvention can also be derived from the following description ofexemplary embodiments and from the figures. All the features describedand/or illustrated individually or in any combination, form basicallythe object of the invention, independent of their combination in theclaims or their back-reference. The content of the claims is made anintegral part of the description.

The expressions “substantially” or “approximately” refer in the contextof the invention to deviations of the respective exact values of +/−10%,preferably of +/−5% and/or deviations in the form of modifications whichare negligible for the function.

BRIEF DESCRIPTION OF THE DRAWING

The invention is described more in detail below in the light of thefigures illustrating exemplary embodiments. The figures are as follows:

FIG. 1 is a diagrammatical illustration of a basic configuration of adevice or forming and filling machine to perform the hydraulic formationof containers by using a filling material;

FIG. 2 a diagrammatical longitudinal section through a preform with apartially inserted stretching rod as well as a venting system;

FIG. 3 shows a diagrammatical longitudinal section through a formedcontainer with a partially inserted stretching and filling device;

FIG. 4 shows a longitudinal section through a forming and filling deviceor station in a modified embodiment;

FIG. 5 shows a longitudinal section through a forming and filling deviceor station with a seal to prevent dripping;

FIG. 6 shows an embodiment with controllable supply of the fillingmaterial and separately controllable venting;

FIG. 7 shows a diagrammatical illustration of a combined forming,filling and closing device or station, and

FIG. 8 shows another embodiment of the combined forming, filling andclosing device or station according to FIG. 7;

FIGS. 9-11 show a diagrammatical sectional view of a further embodimentof the stretching rod of a forming and filling machine or stationaccording to the invention in different process phases;

FIG. 12 shows in a similar representation to FIGS. 10-12 a furthermodified embodiment of the stretching rod of the forming and fillingmachine or station according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The general configuration of a combined forming and filling device ormachine is represented in FIG. 1. Preforms 2 are conveyed from a feedingdevice 1, by using a transfer wheel 3, from a heating device 4. In theregion of the heating device 4, in which the preforms 2 are preheated orthermally conditioned, the preforms 2 can be transported, depending onthe application, for example with their mouth sections 5 upwards invertical direction or downwards in vertical direction. The heatingdevice 4 can for example be fitted with heating elements 6, which arearranged along a transport device 7. A rotating chain for example can beused as a transport device 7. IR or NIR radiators as well as otherenergy-emitting radiators are for example appropriate as heatingelements 6.

After sufficient tempering (also thermal conditioning), the preforms 2are transferred by a transfer wheel 8 to a rotor or process wheel 9,which can be driven to rotate around a vertical machine axis, or toforming and filling stations 10 arranged rotatably, i.e. on the rotor orprocess wheel 9. The process wheel 9 is fitted with a plurality of suchforming stations 19, in the region of which the preforms 2 aretransformed into the diagrammatically represented containers 11, as wellas the containers 11 are filled with the filling material provided.Every container 11 is formed at the same time as it is the filledwhereby the filling material serves as a pressure medium during theforming process.

After forming and filling, the containers 11 are transported away fromthe process wheel 9 by an extraction wheel 12 and conveyed to an outputline 13.

According to the embodiment of FIG. 1, diagrammatically representedclosing members 15 are supplied to the process wheel 9 via a feedingdevice 14. It is thus possible to close hermetically the containers 11on the process wheel 9 and to manipulate fully formed, filled and closedcontainers 11 by using the extraction device 12. The closing member 15be designed for example as a screw-on closure cap, as a crown cap or asa seal film.

Preferably, various thermoplastic materials can be used as a materialfor the preforms 1. By way of example, we may quote polyethyleneterephthalate (PET), polyethylene (PE), polyethylene naphthalate (PEN)or polypropylene (PP). The dimensioning as well as the weight of thepreforms 2 can be adapted to the size, the weight and/or the design ofthe containers 11 to be manufactured.

A plurality of electrical and electronic components is arrangedtypically in the region of the heating device 4. Moreover, the heatingelements 6 are fitted with moisture-sensitive reflectors. As thecontainers are filled and formed in the region of the process wheel 9 byusing the liquid filling material, it must be ensured that anyunintentional ingress of moisture into the region of the heating device4 is prevented. This can for instance be in the form of a partitioning16 which at least provides a splashguard. Moreover, it is also possibleto temper the transport elements for the preforms as appropriate in theregion of the transfer wheel 8 or to act upon them with thrusts ofcompressed gas in such a way that any adhering moisture cannot reachinto the region of the heating device 4.

The preforms 2 and/or the containers 11 can be manipulated preferablyusing claws and/or clamping or plug-in elements acting upon the mouthsection 5 at least in certain areas from the inside or from the outside.

FIG. 2 shows a longitudinal section through a preform 2 into which astretching bar or a stretching rod 17 is inserted. The stretching rod 17serves for at least temporary guiding of the preform 1 during itstransformation to the container 11. Typically, there is a contactbetween a point 18 of the stretching rod 17 and a bottom 19 of thepreform 2. The preform 2 is stretched longitudinally when the stretchingrod 17 penetrates further into the preform 2. Upon completion of thestretching cycle or at least temporarily during the performance of thestretching cycle, the filling material 21 extracted from a supply device20 is conveyed into the preform 2.

The filling material 21 is metered by using a multi-way metering valve22. In the exemplary embodiment represented, the stretching rod 17 is atleast in certain areas hollow or has a duct and the filling material 21is conveyed to a cavity 23 of the stretching rod 17. The region of awall of the stretching rod 17 includes outlet openings 24 which can beshut off by a return valve 25 with respect to the multi-way meteringvalve 22. This enables to avoid or to minimize unintentional dripping ofthe filling material 21 from the stretching rod 17.

The preform 2 can be vented by using a venting valve 26. The ventingvalve 26 is connected to an outlet opening 27 which is arranged in theregion of a connecting element 28 acting upon the preform 1. Thestretching rod 17 can be positioned through the connecting element 28.The preform 2 is sealed by a gasket 29 with respect to the connectingelement 28, which can be in the form of an O-ring for instance. A cavity30 of the preform 2 can be connected to the outlet opening 27 via anannular slit 31. To do so, the annular slit 31 surrounds the stretchingrod 17.

FIG. 3 shows diagrammatically a similar device as in the illustrationaccording to FIG. 2 by using a hollow stretching rod 17 with a built-inreturn valve 25. An already fully formed container 11 is howeverrepresented. FIG. 2 as well as FIG. 3 clearly show that preferably aplurality of outflow openings 24 is arranged in the region of thestretching rod 17. With the exemplary embodiment represented, suchoutlet openings 24 are positioned at different height levels along alongitudinal axis 32 of the stretching rod 17. Likewise, the exemplaryembodiment represented shows an orientation of the outlet openings 24with a substantially horizontal outlet direction. The arrangement of theoutflow openings 24 in the region of the stretching rod 17 as well asthe orientation of the outflow openings 24 can be varied. The aim is toprovide typically the quietest and the most splash-free outflowbehavior.

In accordance with the invention, there is furthermore diagrammaticallyshown a device for supplying dry ice 70, with which in the secondprocess phase dry ice, in the present example in the form of pellets,can be shot from an insulated storage tank 71 into the developing or thealready formed container. The foaming of the filling medium afterrelieving the container can thereby be delayed until the container isclosed. At the same time, it is possible to fill a filling medium havinga high CO₂ content in the containers.

According to the embodiment of FIG. 4, a massive stretching rod 17 isused. The filling material 21 is supplied along at least a flow ductpast the stretching rod 17. Preferably, the annular slit 31 is used todo so. Also with this embodiment, it is possible to perform a targetedventilation.

FIG. 5 shows an embodiment with a stretching rod 17 possessing anoptimised form to prevent any dripping. A sealing element 33 istherefore arranged in the region of the tip 17. The sealing element 33can for example be provided by enlarging the diameter of the stretchingrod 17. Likewise, an appropriate selection of materials can beenvisaged. When retracting the stretching rod 17 from the container, thesealing element 33 enters into contact with a counter element 33 whichis arranged in the region of the connecting element 28. The counterelement 34 is preferably designed as a gasket. The outlet openings 24 ofthe stretching rod 17 are arranged separately and sealed from thecontainer 11 after appropriate positioning of the stretching rod 17 sothat dripping from the cavity 23 of the stretching rod 17 can be avoidedreliably. Typically, at least one bearing 35 is arranged in the regionof the connecting element 28 for guiding the stretching rod 17.

FIG. 6 shows a form of embodiment in which again a massive stretchingrod 17 is used. The multi-way metering valve 22 for the filling material21 as well as the venting valve 26 are connected to the cavity 30 of thepreform 2 or of the container 11 via flow ducts running past thestretching rod 17, in particular through the annular slit 31. In theexemplary embodiment represented, the outlet opening 27 is arranged in aradial direction of the connecting element 28 opposite to a supplyopening 36 which is connected to the multi-way metering valve 22.

FIG. 7 shows an embodiment in which the containers 11 are also closedhermetically in the region of the process wheel 9 according to FIG. 1.The container 11 is still arranged in the region of a mould 37 whichforms a portion of the forming station 10 according to FIG. 1. A closingdevice 38 is arranged coaxially to the connecting element 28 withrespect to the longitudinal axis 32 in this embodiment. The closingdevice 38 includes for example grippers 39 mounted pivotably which areprovided for acting upon the closing element 15. The idea behind that inparticular is to arrange the closing device 38 rotatably with respect tothe connecting element 28. Thereby, the closing member 15 can be screwedwith an internal thread on an external thread of the mouth section 5.

FIG. 8 shows an alternative form of embodiment for the constructionaccording to FIG. 7. The closing device 38 and the connecting element 28are here not arranged coaxially relative to one another but arepositioned by a tool carrier 40 alternately in a working arrangement orin a resting arrangement. The tool carrier 40 can be designed forexample in a revolver-type arrangement and be fitted with a rotationalaxis 41.

Certain process-typical parameters are for example described more indetail below. The filling material 21 is supplied to the connectingelement 28 preferably with a temperature of the surrounding room, forexample in the range of 20° C. to 30° C. The filling material 21 therebycools the material of the container 11 and supports a rapid formstability of the formed container 11. This provides a very short cycletime. Likewise, it is also possible to supply the filling material 21once it has been cooled or heated up more strongly.

During the forming of the container 11, the filling material 21 can beintroduced at least temporarily with a constant volume flow rate intothe preform 2 or into the container 11.

But it is also possible to provide for the volume flow rate anappropriate temporal profile in such a way that different volume flowrates are generated at different points in time.

Before introducing the filling material 21 it is possible to suck awaythe air situated inside the preform 1 and/or to replace it with an inertgas. This is particularly recommended with oxidation-sensitive fillingmedia 21.

As filling material 21, either pure liquids or liquids provided withadditives, can be used. The supply of carbonized filling media isconsidered in particular. Since the filling material 21 is supplied tothe preform 1 or to the container 2 under pressure, for instance with apressure of 10 bars, it appears appropriate to design all the flow pathsfor the filling material 21 in such a way that local decompressions areprevented by the flow processes. Otherwise, a local or temporarydecompression could lead to outgassing of the carbon dioxide.

Alternatively to the heating represented in FIG. 1 of preferablyinjection-moulded preforms 2, it is also possible to produce thepreforms 2 immediately before their transformation into the containers11. This can be realized for example using an injection-molding processas in a so-called single-stage injection blow method; a compressionforming process is likewise possible. Such a forming of the preforms 2avoids using electrical and electronic components in the region of aheating device or at least reduces substantially the extent of use ofsuch parts since the latter are only required for possibly necessarytemperature profiling.

Corrosion-resistant substances are preferably used as materials for thecomponents of the process wheel 9, in particular stainless steels aswell as plastics. In particular, the moulds 37 can be made totally orpartially out of an appropriate plastic.

In order to minimize the necessary stretching forces, it is possible tosupport the stretching cycle by the supply of the filling material 21.When supporting the stretching cycle in this way, it must however beassured that the preform 2 is guided by the stretching rod 17. Theoperation may for instance consist in measuring the acting stretchingforce and in controlling the volume flow rate of the filing material 21in such a way that a minimum stretching force is always maintained. Themagnitude of the stretching force can be determined in particular quiteeasily with electrically driven stretching systems by measuring thedrive current or with pneumatic stretching systems by measuring thepressure.

When filling containers 11 with the filling material 21 it is oftendesirable to provide a gas-filled headroom after closing the containerhermetically 11. Said free headroom can be generated by the volumereduction which results from the retraction of the stretching rod 17.

The selection of materials already mentioned above takes given hygienerequirements into account. Degermination or sterilization can thus beguaranteed. The construction design shall be carried out in such a waythat the requirements in good cleanability are fulfilled.

One or several of the transfer wheels can be fitted with servo drives.

This supports in particular a complete separation of the heating device4 from the process wheel 9 during cleaning cycles. Likewise, in theregion of at least one of the transfer wheels, retractable manipulationelements may be arranged. The use of a dry air tunnel can provide afurther protection against moisture.

By way of example, a concrete process flow is described below. Before orafter inserting the preform 2 into the mould 37, there is first of all agas exchange in the cavity of the preform, in order to repel oxygen inparticular or to reduce the portion of oxygen. The flushing and/orexhaust cycle lasts typically at most 0.1 second. The stretching of thepreform 2 by using the stretching rod 17 lasts typically approx. 0.2second. Likewise, a time span of approx. 0.2 second is provided for thefilling and the resulting transformation of the preform 2 into thecontainer 11. A maximum time span of 0.2 second is typically requiredfor the subsequent creation of a headroom. The container filled withstill beverages can be calmed down and relieved from tension extremelyfast, whereas with carbonated beverages, this cycle can take a time spanof up to 5 seconds.

The headroom can be treated subsequently for example by using ahigh-pressure foaming or by feeding oxygen. The subsequent supply of aclosing cap can take a time span of up to 1.5 seconds with carbonatedbeverages. Likewise, the closing or screwing cycle takes for instance atime span of 1.5 seconds.

Once the container 11 has been closed hermetically, the mould 37 opensand the filled container 11 is removed and transported away.

When inserting the filling material into the preform 2 to be transformedor into the container 11 still in the forming process there is usually atypical pressure gradient in the filling system or in the preform 2 ormore precisely the container 11 still in the forming process. Due to theexpansion of the container 11, there is first of all a relatively lowpressure which increases till the end of the forming cycle. Thecorresponding pressure rise or the height of the pressure rise in thefilling system, in particular in the filling conduit, can be used as acontrol parameter for a following process step and if applicabledetermine the moment of introduction of said next process step.Alternately or in addition thereto, the characteristic of the pressuregradient and/or of the volume flow rate of the filling material can beused as control parameters.

As regards the temperature of the filling material, the filling materialmay be conveyed with a surrounding temperature. Depending on therespective conditions of application, instead of filling at surroundingtemperature, a temperature increase or a temperature decrease can becontemplated.

According to a further variation, the filling process may be implementedin two stages, whereas during the first process step the fillingmaterial is conveyed at a temperature which is higher than thetemperature during the second process step. The first process step canfor example be carried out when the longitudinal stretching of thepreform 2 is performed over the stretching rod 11. The second processstep follows the performance of the stretching cycle and corresponds tothe transversal expansion of the container 11.

During the aforementioned appeasement in the headroom after pressurerelief, it may also be carried out an aspiration of developing gasesand/or foam, if applicable.

As regards the closing of the finished formed and filled containers 11,different variations can also be realized. In a variation, it ispossible to fit a portion of the manipulation or forming and fillingstations 10 on the rotor or process wheel 9 with a revolver head. Therevolver head includes on the one hand a blowing or forming and fillinghead and on the other hand a closing head. This corresponds to thediagrammatical representation of FIG. 8. Likewise, it is alsocontemplated to use an integrated construction with which the respectivehead carries out the blowing, the filling and the closing cycle.

According to a further variation, the forming and filling head as wellas the closing head are designed as separate components, but arranged topivot at every forming and filing station 10. According to a thirdvariation, only the forming and filling head is provided on the rotor orprocess wheel 9 and the container still open is transferred to aseparate closing system, for example to a transport wheel, which isfitted with a closing head.

The application of the closing elements 15, for instance of the closingcaps, can take place immediately after opening the respective mould 37and the gripping of the container 11 via a holding and gripping element.An advantageous variation consists in maintaining the mould 37 closedand hence to fix the container 11 in correct position, whereas only themouth is released for a closing element. Said release takes place inmoving the mould 37 either for an angular distance on a radiallydifferent position or in pivoting and/or moving the forming and fillinghead so that the container mouth is free for a closing element.

To do so, the closing caps would be placed on the rotor or the processwheel 9. In particular, an inert gas may be applied to the mouth spaceof the filled container 11 before positioning the closing elements 15.

In the above description it was considered for simplifying purposes thatonly one supply device 20 is provided for the filling material 21. Infact, the forming and filling system or machine includes a furthersupply device 20.1 for an additional portion or a further component ofthe filling material, which exhibit a higher CO₂ content than thefilling material 21 and is designated below with 21.1.

It has proved particularly advantageous to achieve stratification withthe aforementioned methods and in particular with respect to theintroduction of the portion or of the component of the filling material21.1 with a CO₂ content or with the higher CO₂ content. It has namelyappeared problematic in the case of a full or partial carbonization ofthe filling material, to obtain the rapid pressure relief after removalfrom the mould and filling of the containers 11, from the high formingand filling pressure up to the closing of the respective container forinstance at ambient pressure without product loss. A massive foamingoccurring here with product loss has prevented the use of this hydraulictransformation technique for CO₂ containing products so far.

According to a cognition underlying the invention, it is particularlyadvantageous to avoid such product losses if the filling material 21 or21.1 or the portions of the filling material 21 or 21.1 are supplied atleast at two points in time or in at least two process phases withdifferent carbon dioxide contents and/or with different temperatures. Todo so, it is appropriate in a second or subsequent process phase, tofeed the filling material or the filling material component 21.1 withthe higher concentration of carbon dioxide. This has the advantage thatthe filling material 21 and 21.1 in the generated container 11 commonlyconstitute the hydraulic pressure medium to form the container 11, butthe filling material 21 already introduced in the developing container11 has calmed down and when introducing the filling material 21.1 or theportion of filling material 21.1 with the higher CO₂ concentration,first of all further solution processes take place in the liquid volume.The second or subsequent process phase is thereby for instance a processphase completing the forming and filling phase. The introduction of thefilling material 21.1 or of the portion of filling material 21.1 withthe higher CO₂ concentration is preferably stratified into the alreadypresent liquid volume, i.e. for instance in the region of the bottom ofthe developing container 11. The introduction of the filling materialcomponents or of the filling material 21 and 21.1 takes place in acontrolled manner through the multi-way metering valve 22.

There is a variation which consists in cooling the filling material 21.1or the portion of filling material 21.1 with the higher concentration ofcarbon dioxide before introduction, and in that in the aforementionedsecond process phase introducing said filling material 21.1 or thecorresponding portion with the higher concentration of carbon dioxidewith a lower temperature than the filling material 21 or the portion offilling material 21 of the first process phase into the developingcontainer 11. The result is a lower layer with a filling material richin CO₂, whereas a foaming, also a foaming during the relieving processis decreased to the extent that disadvantageous product losses do notoccur.

Therefore, the carbon dioxide content in the second process phase shouldbe 30% in weight above the carbon dioxide content during the firstprocess phase, in particular 50% in weight to 100% in weight above thecarbon dioxide content in the first phase. Ideally, during the first orinitial process phase, a quiet, i.e. a filling material component freefrom CO₂, such as the filling material 21 and during the second processphase a filling material component rich in CO₂, i.e. the fillingmaterial 21.1, are introduced into the developing container 11.

There is an alternative in which the temperature of the filling material21.1 or of the portion of filling material 21 of the second processphase is cooled, in which it is at least 10° C. below the temperature ofthe first or a previous process phase, and in particular is lower than10° C. and ideally ranges between 4° C. and 8° C.

It has appeared advantageous that the pressure of the filling material21.1 or of the portion of filling material 21.1, which exhibits thehigher carbon dioxide concentration and/or the lower temperature, atleast during the transformation process or during the forming andfilling phase is partially higher than the pressure of at least anotherportion or of the residual portion of the filing material 21, andpreferably by at least 1 bar.

Moreover, the pressure on a conduit section 42 or a portion of theconduit section, via which the filling material 21.1 or the portion ofthe filling material 21.1 with the higher carbon dioxide concentrationand/or the lower temperature is conveyed, is higher than the pressure ofthe residual filling material 21 or of the residual portion of thefilling material 21, and during the shaping process at least temporarilyhigher by 2 bars to 5 bars.

An embodiment provides that a throttle element or a narrowingcross-section is provided in the flow path of the filling material 21and 21.1 flowing inside the stretching bar 17, whereas the throttleelement is arranged in the flow direction of the filling material 21 and21.1 for instance shortly before at least one output 24 of thestretching rod 17. Consequently, the advantageous high pressure ismaintained up to shortly before the first relaxation. This pressure canbe raised further when a portion of the filling material 11 is guidedpast the horizontal rod 17 and a portion of the filling material 11 isguided through the horizontal rod. To do so, the stronger carbondioxide-containing filling material 21.1 should be conveyed moreappropriately through the stretching rod 17. It is also advantageous ifthe stretching rod 17 is thermally insulated at in a section withrespect to the filling material 21 and 21.1.

The forming and filling system or machine thereby encompasses forproducing filled containers 11 made of a thermoplastic material amongothers the at least one heating section or heating system 4 arrangedalong a transport path of a preform 2 and at least one forming andfilling station 10 fitted with a mould.

Moreover, the forming and filling system or machine encompasses amongother things a feeding device 1 for the filling material 21 and 21.1 tobe filled into the container 11 as well a carbonization unit 43, whichfor example is provided in the conduit section 42 and with which carbondioxide can be dissolved at least in the partial flow of the fillingmaterial 21.1, whereas the forming and filling station 10 has a guidingdevice in the form of a stretching rod 17 acting at least temporarilyupon the preform 2 during its transformation into the container 11 andat least one portion of the filling material 21 can be conveyed throughthe duct or the cavity 23 of the stretching rod 17. At least one outletopening 24 of the conduit or cavity 23 is provided at the lower end ofthe stretching rod 17.

Advantageously, a cooling unit 44 is provided at least along the conduitsection 42 for the filling material 21.1, in which downstream carbondioxide is dissolved or which flows from the carbonation unit 43.

At least the conduit section 42, in which the filling material 21.1 richin carbon dioxide or a portion thereof is guided, at least thermallyinsulated on a partial length, for example with a Teflon insulation ormade of a Teflon-containing material, and/or is cladded with a thermalinsulation, for instance with Teflon or a Teflon-containing material.

FIGS. 9-11 show in a partial and sectional representation a stretchingrod 17 a, which corresponds to the stretching rod 17 in its basicfunction, i.e. serves during the forming and the filling of therespective preform 11 for guiding and for controlling in particular theaxial stretching of the respective preform 2 or of the developingcontainer 11. The stretching rod 17 a mainly consists of a bar-shapedstretching rod body 45 with a rounded free stretching rod end 45.1.Several ducts are arranged in the stretching rod body 45, namely aninternal duct 46 arranged coaxially with the longitudinal axis of thestretching rod 17 a, which emerges in the vicinity of the end 45.1 atseveral outlet openings 47 distributed around the axis of the stretchingrod 17 a on the lower level N1, as well as an external annular duct 48surrounding the internal duct 46 and separate from said internal duct,which external duct emerges at several upper outlet openings 49distributed around the axis of the stretching rod 17 a, at thesurrounding or envelope surface of the stretching rod 17 a on the upperlevel N2. A control valve designated with 50 in FIG. 9 is moreoverprovided in the inside of the stretching rod 17 a, a valve with which aconnection can be established or interrupted between the internal duct46 and the external duct 48 in a controlled manner. The control valve 50is formed substantially of an axially movable lock ring 51 in therepresented embodiment, which is preloaded for example by a spring, notrepresented in detail, in its raised position in FIG. 9 and its positionreleasing the connection between the ducts 46 and 48. The lock ring 51is mobile against the effect of the spring in its position interruptingthe connection between the ducts 46 and 48 by an actuating device, forinstance through a magnet coil 52 housed in the stretching rod 17 a.

FIGS. 9-11 represent moreover the multi-way metering valve 22 controlledby the electronic control unit 53, a valve which is again designed as amultiway valve, which is connected to a first connection or inlet withthe supply device 20 not represented in FIG. 9 for the filling material21 and which is associated with a second connection with the supplydevice 20.1 not represented in FIG. 9 for the filling material 21.1. Theoutlets of the multi-way metering valve 22 are associated via a liquidconnection 54 with the internal duct 46 or via a liquid connection 55with the external annular duct 48. The cooling unit 44 is arranged inthe liquid connection 54. The control valve 50 or its magnet coil 52 iscontrolled by the control unit 53, whereas the control valve 50 isrealized in the represented variation as an electromagnetically,linearly driven system. This has the particular advantage to be able toadjust the closing and opening speeds continuously. It is therefore notnecessary to design the control valve 50 to 100% in a tight manner, asmall amount of leak can be tolerated.

Different operating modes are possible with the stretching rod 17 a,namely for example the simultaneous introduction of the fillingmaterial, for example of the filling material 21 without CO₂ content orwith reduced CO₂ content on the lower level N1 via the outlet openings47 and on the higher level N2 via the outlet openings 49 into thepreform 2 or into the developing container 11. Therefore, the controlvalve 50 is opened by suitable control from the control unit 53 for aconnection of both ducts 46 and 48 and moreover the multi-way meteringvalve 22 is controlled through the control unit 53 in such a way thatthis metering valve only provides a connection with the liquidconnection 55. Said operating condition is represented in FIG. 9.

With a closed control valve 50, it is moreover possible to establish aconnection to both ducts 46 and 48 by a suitable control of themulti-way metering valve 22 via said valve for the filling material 21so that the filling material 21 is again inserted according to thearrows via the outlet openings 47 and 49 at the different levels ofheight N1 and N2 into the preform 2 or into the developing container 11.In the operating condition represented in FIG. 10, there is still thepossibility to cool the partial quantity of the filling material 21 inthe cooling unit 44, a quantity fed to the internal duct 46 and exitingthe lower outlet openings 47, or to cool the liquid connection 54 for achronologically following process step with the filling material.

Moreover, there is the possibility, by suitable control of the multi-waymetering valve 22, to supply the filling material 21.1 via the liquidconnection 54 in the internal duct 46 for the exit exclusively at thelower outlet openings 47 or on the high level N1 and to supply thefilling material 21 for the exit exclusively at the upper outletopenings 49 or on the higher level N2, whereas the supply of the fillingmaterial 21 and 21.1 is either simultaneous, time-delayed or with a timeoverlap, and namely with an evacuation which is time-delayed or with atime overlap preferably in such a form that first of all the fillingmaterial 21 is supplied via the upper outlet openings 47 and then thefilling material 21.1 is supplied via the lower outlet openings 49. Saidoperating condition, in which again the filling material 21.1 is cooledin the cooling unit 44, is represented in FIG. 11. It goes withoutsaying that the various operation conditions represented in FIGS. 9-11can be combined at will in the respective forming and filling phase.

It is for example possible during the respective forming and fillingphase in a first partial or process phase according to FIG. 9 tointroduce the filling material 21 via the outlet openings 47 and 49 in achronologically following second partial or process phase according toFIG. 10 to introduce the filling material 21 via the outlet openings 47and 49 further and hence simultaneously to pre-cool the liquidconnection 54 with the filling material 21 flowing through the coolingunit 44 and then according to FIG. 11 in a third partial or processphase to introduce the filling material 21.1 via the lower outletopenings 47, whereas for example the filling material 21 is furthersupplied via the upper outlet openings 49.

A calmed intermediate zone is formed in each of the cases between theheight levels N1 and N2, a zone which delineates the portions of fillingmaterial from each other. An advantageous influence lies in theaforementioned electromagnetically driven control valve 50, because itenables a low-impulse and low-blending changeover. A further advantageconsists with said electromagnetically driven control valve 50 that itis quite robust and can be cleaned very easily in corresponding cleaningcycles using quick, and, if necessary, multiple switching.

FIG. 12 shows a simplified sectional view of a further embodiment of astretching rod 17 b, which differentiates from the stretching rod 17 asubstantially only in that in addition to both ducts 46 and 48 a thirdannular duct 56 is provided in an upper region, remote from thestretching rod end 45.1, a duct which emerges at several outlet orrelief openings 57 distributed around the axis of the stretching rod 17b at the surrounding or envelope surface of the stretching rod 17 b. Theheadroom 59 formed in the container 11 above the surface of the fillingmaterial is relieved via the duct 56 for example by a control valve 58driven by the control unit 53 after forming and filling the respectivecontainer 11. The container 11 can be further relieved after forming andfilling via the outlet openings 47 and when the control valve 50 isopen, also via the outlet openings 49, for example by a control valve 60driven by the control unit 53.

The stretching rods 17 a or 17 b represented in FIGS. 10-13 or theforming and filling devices or machines having said stretching rods alsoenable to evacuate the respective preform 2 before starting the formingand filling phase and/or to rinse it for example with a hot inert gas,and preferably via the lower outlet openings 47.

As shown in FIGS. 9-12, the outlet openings 47 and 49 or the stretchingrod 17 a are designed at their surrounding or envelope surface in such away that the main flow direction of the medium exiting the outletopenings 47 or 49 with respect to the longitudinal axis of thestretching rod 17 a is tilted in an angle smaller than 90°, namely atthe lower outlet openings 47 in such a way that said angle opens at thelower stretching rod end 45.1 and at the upper outlet openings 49, thatsaid angle opens towards the end of the stretching rod 17 a facing awayfrom the lower stretching rod end 45.1.

The outlet openings 47 or 49 have in particular rounded edges or radiiso that local turbulences and cavitation are avoided and result in astable stratification. More advantageously, the rounded edges of theoutlet openings 47 and 49 are provided at the stretching rod radiallyand inwardly as well as radially and outwardly.

LIST OF REFERENCE SIGNS

-   1 Feeding device-   2 Preform-   3 Transfer wheel-   4 Heating device-   5 Mouth section-   6 Heating element-   7 Transport device-   8 Transfer wheel-   9 Process wheel-   10 Forming and filling station-   11 Container-   12 Extraction wheel-   13 Output distance-   14 Input device-   15 Closing member-   16 Mould partitioning-   17 Stretching bar or stretching rod-   17.1 Narrowing portion-   18 Tip of the stretching rod-   19 Bottom of the preform-   20 Supply device-   21 Filling material-   22 Multi-way metering valve-   23 Cavity of the stretching rod-   24 Outlet opening-   25 Return valve-   26 Venting valve-   27 Outlet opening-   28 Connecting element-   29 Seal-   30 Cavity of the preform-   31 Annular slit-   32 Longitudinal axis of the bottle or-   33 Sealing element-   34 Counter element-   35 Bearing-   36 Supply opening-   37 Mould-   38 Closing device-   39 Gripper-   40 Tool carrier-   41 Rotational axis-   42 Conduit or conduit section-   43 Carbonation unit-   44 Cooling unit-   45 Stretching rod body-   45.1 Stretching rod end-   46 Duct-   47 Outlet opening-   48 Duct-   49 Outlet opening-   50 Control valve-   51 Lock ring-   52 Magnet coil-   53 Control electronics-   54,55 Liquid connections-   56 Duct-   57 Outlet opening-   58 Control valve-   59 Headroom-   60 Control valve-   70 Feeding device for dry ice pellets-   71 Storage tank for dry ice pellets

The invention claimed is:
 1. A method for producing containers filledwith a liquid filling material from preforms made of a thermoplasticmaterial, the method comprising the steps of: thermally conditioning arespective preform and subsequently transforming the preform during aforming and filling phase in a mold with at least one liquid fillingmaterial as pressure medium so as to simultaneously form and fill thecontainer; supplying the filling material or portions of the fillingmaterial in at least two process phases with different carbon dioxidecontents; and in a second of the process phases providing the liquidfilling material with a desired carbon dioxide concentration byintroducing dry ice formed as pellets while the container is beingformed.
 2. The method of claim 1, wherein degassed filling material isconveyed in a first of the process phases.
 3. The method of claim 1,wherein in the second process phase chronologically following a first ofthe process phases the filling material or the portion of fillingmaterial with a higher concentration of carbon dioxide is supplied. 4.The method of claim 1, wherein the preform is guided duringtransformation into the container at least temporarily via a stretchingrod and is stretched in axial direction.
 5. The method of claim 4,wherein the dry ice is inserted into the filling material or shot intothe filling material.
 6. The method of claim 4, wherein the fillingmaterial or the portion of filling material with the higherconcentration of carbon dioxide is cooled before introduction, and/or inthe second process phase the filling material or the portion of fillingmaterial with the higher concentration of carbon dioxide has a lowertemperature than the filling material or the portion of filling materialof the first process phase.
 7. The method of claim 1, wherein the carbondioxide content of the filling material or of the portion of fillingmaterial in the second process phase is at least 30% in weight greaterthan the carbon dioxide content of the filling material or of theportion of filling material of the first process phase.
 8. The method ofclaim 7, wherein the carbon dioxide content of the filling material orof the portion of the filling material in the second process phase is 50to 100% in weight greater than the carbon dioxide content of the fillingmaterial or of the portion of filling material of the first processphase.
 9. The method of claim 1, wherein the temperature of fillingmaterial or of the portion of filling material of the second processphase is lower than 10° C.
 10. The method of claim 9, wherein thetemperature is between 4° and 8° C.
 11. The method of claim 6, wherein apressure of the filling material or of the portion of filling materialwith the higher carbon dioxide concentration and/or the lowertemperature, is at least temporarily higher than a pressure of at leastone other portion or of a residual portion of filling material by atleast 1 bar.
 12. The method of claim 11, wherein a pressure on a sectionof a conducting path is higher than the pressure of the filling materialor of the portion of the filling material which has the higher carbondioxide concentration and/or the lower temperature, and during theforming and filling phase or during the shaping process is at leasttemporarily higher by 2 bars to 5 bars than a pressure of at least oneother portion or a residual portion of the filling material.
 13. Themethod of claim 11, including providing a throttle element or anarrowing cross-section in a flow path of the filling material or of theportion of the filling material flowing inside the stretching rod,whereas the throttle element is arranged before at least one fillingmaterial discharge.
 14. The method of claim 4, including guiding aportion of the filling material past the stretching rod and guiding aportion of the filling material through the stretching rod.
 15. Themethod of claim 4, including cooling the filling material with a higherconcentration of carbon dioxide-containing or the portion of saidfilling material, and/or guiding at least the filling material with thehigher concentration of carbon dioxide or the portion of said fillingmaterial through the stretching rod.
 16. The method of claim 4, whereinthe stretching rod is thermally insulated at least in certain sectionswith respect to the filling material.
 17. The method of claim 1, whereinthe filling material or the portion of the filling material withoutcarbon dioxide or with a reduced concentration of carbon dioxide isintroduced into the preform into the container in formation in a firstof the process phases through at least two filling material outlets atdifferent height levels, and in the chronologically following secondprocess phase of the forming and filling phase at least said fillingmaterial or the portion of filling material with a higher concentrationof carbon dioxide is introduced into the preform or into the formingcontainer at a lower height level, whereas the filling material or theportion of filling material Without carbon dioxide or with the reducedconcentration of carbon dioxide is introduced in the second processphase or a greater height level above the lower height level.
 18. Themethod of claim 17, wherein in a third process phase between the firstand second process phase a liquid connection is pre-cooled by cooledfilling material or a cooled portion of filling material without carbondioxide or with the reduced concentration of carbon dioxide, the liquidconnection through which in the second process phase the fillingmaterial or the portion of filling material with the higherconcentration of carbon dioxide is guided for introduction into thepreform or into the container in formation.
 19. The method of claim 1,wherein the process phases are partial phases of the forming and fillingphase.